Electrical coil



March 8, 1955 P. EISLER 2,703,854

' ELECTRICAL con.

Original Filed Feb. 3, 1944 3-msuLA'Trou 6- INSULATION FlG. 'l

IN VEN TOR. PAUL EISLER ATTORNEY United States Patent O ELECTRICAL COIL Paul Eisler, London, England, assignor of one-half to Hermoplast Limited, London, England, a corporation of Great Britain Original application February 3, 1944, Serial No. 520,991,

now Patent No. 2,441,960, dated May 25, 1949. Divided and this application May 26, 1948, Serial No. 29,377.

1 Claim. (Cl. 336-200) The present invention relates to electrical coils or windings, and in particular to windings comprising a plurality of electric conductors formed upon or secured to a strip of insulating material.

Recently developed methods of manufacturing the conductive metallic elements of electrical and electronic equipment, such as described in Patents 2,441,960 and 2,587,568 have markedly altered the heretofore conventional form of such elements. Ordinary wiring, for example, is being replaced by electrically conductive narrow strips or lines formed upon and aflixed to an insulating base by what is now commonly known as printed circuit techniques, the products produced thereby, being referred to as printed circuit products.

Broadly speaking, the invention provides for the transformation of a plurality of electric conductors secured to a strip of insulating material, into an electric winding or coil.

Accordingly, it is a primary object of the invention to provide a means by which strips of insulating sheet material bearing a plurality of conductors may be utilized to form electrical windings or coils of the type employed for instance in transformers, inductances, and other electrical equipment.

It is a further object of this invention to provide a means for joining said conductors after the strip has been wound.

A more specific object of the invention is to provide a unique and highly versatile connecting label which allows the insulation strip beating the conductor to be transformed into an electrical coil.

In the accompanying drawing a now preferred, embodiment of the invention is shown by way of illustration and not by way of limitation.

In the drawing:

Fig. 1 is a plan view of a connecting label according to the invention and of two end sections of a strip of insulating material bearing a plurality of conductors, and

Fig. 2 is a fragmentary sectional view of the label and of one of the end sections, the label and the end section being in the position for final assembly.

Fig. 1 shows the two ends 1 and 2 of a long strip of flexible insulation 3 bearing a pattern of parallel metallic lines 4 which can be produced in any desirable numbers by the printed circuit techniques hereinbefore referred to. There are no end connections between the lines. This pattern is here used as the basis for making a helical winding to serve as an inductance, or as the winding of a transformer or for like purposes. After its production the strip is wound upon a former or upon a core. It would ordinarily be a very 2,703,854 Patented Mar. 8, 1955 tedious operation to wind a wire winding upon a closed core such as is often used in a transformer, perhaps involving threading the bobbin through the core some thousands of times. But when it is remembered that the strip of Figure 1 may have hundreds of conductors side by side, it will be understood that thousands of turns of wire may be wound about a core by threading such a strip through it only a few times. However, the winding of the strip on the core in this manner only leaves the core winding with, say a thousand separate conductors each encircling the core a few times. It remains to join these conductors in series, which involves, say, joining the end of the lowermost conductor in the end 1 of the strip to the uppermost in the end 2 and so on. This is conveniently done by the aid of a label 5 of transparent insulating material 6 bearing a pattern of parallel conductors 4 of similar spacing to the conductors of the strip ends 1 and 2 insulated at their middle parts 7, by an insulating substance coated thereon, but bare and solder-painted at their ends 8. The label is provided with lead-in and lead-out terminals 13 and 13'. In order that this label may be accurately applied to the ends 1, 2, as is necessary considering the close spacing of the conductors, the label not only carries the conductors but is embossed, so that the ends of its conductors lie in grooves 9. Figure 2 shows the embossed part of the label superimposed upon the end 2 of the strip. It will be seen that the embossed parts of the label will fit between the conductors 4 of the strip and thereby cause the conductors of strip and label to be accurately superposed. A soldered joint is made by heat and pressure. The flaps 10 of the label may be coated with adhesive and folded around and made adherent to the back of the ends 1 and 2. Dotted lines 11 and 12 indicate the fold lines.

This application is a division of application Ser. No. 520,991, filed February 3, 1944, now Patent 2,441,960, issued May 25, 1949.

I claim:

An electric winding comprising a length of flexible sheet insulating material, a plurality of separate sheet metal strips adherent to the face thereof and extending lengthwise thereof, an adhesive insulating label securing together the ends of said insulating material, so forming a closed loop, and metallic members on said label each having its ends spaced laterally in relation to said strips, said members contacting with and so interconnecting the ends of two different strips in an ordered succession thereby to connect said strips into at least one winding comprising a plurality of turns.

References Cited in the file of this patent UNITED STATES PATENTS 460,725 Markle Oct. 6, 1891 1,334,276 Adams Mar. 23, 1920 1,563,731 Ducas Dec. 1, 1925 1,647,474 Seymour Nov. 1, 1927 1,718,993 Wermine July 2, 1929 1,794,831 Caruso Mar. 3, 1931 1,939,130 Mills Dec. 12, 1933 2,343,306 Lear Mar. 7, 1944 2,370,846 Deakin Mar. 6, 1945 2,399,753 McLarn May 7, 1946 2,427,144 Jansen Sept. 9, 1947 2,450,974 Mallina Oct. 12, 1948 FOREIGN PATENTS 327,356 Great Britain Apr. 3, 1930 

